Definition
Scoria is a dark-colored extrusive igneous rock with abundant round bubble-like cavities
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Discoverer
Unknown
Unknown
Etymology
From late Middle English (denoting slag from molten metal), from Greek skōria refuse, from skōr dung
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock
Texture
Vesicular
Porphyritic
Color
Black, Brown, Dark Grey to Black, Red
Blue, Bluish - Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Glassy and Vesicular
Foliated
Interior Uses
Decorative Aggregates, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, In landscaping and drainage works
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Commercial Uses
As a traction material on snow-covered roads, Creating Artwork, High-temperature insulation, In gas barbecue grills
Cemetery Markers
Types
Basaltic Scoria and Andesitic Scoria
Rhyolite
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Surfaces are often shiny
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Formation
Scoria forms when magma containing huge amount of dissolved gas flows from a volcano during an eruption.
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Apatite, Biotite, Calcite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz, Silica
Albite, Amphibole, Quartz
Compound Content
Ca, NaCl
Al, Fe, Potassium Oxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Coastal Erosion, Water Erosion
Grain Size
Fine Grained
Medium Grained
Fracture
Conchoidal
Pervasive
Streak
White
Bluish Black
Porosity
Highly Porous
Highly Porous
Luster
Subvitreous to Dull
Dull
Specific Gravity
-9999
2.38
Transparency
Opaque
Opaque
Density
-9999 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
China
Africa
Ethiopia, Kenya, Tanzania
East Africa
Europe
Greece, Hungary, Iceland, Italy, Turkey
Italy
Deposits in Western Continents
North America
Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA
-
South America
Argentina, Chile, Ecuador, Peru
-
Deposits in Oceania Continent
Australia
New Zealand, Western Australia
Queensland